This invention relates generally to heavy duty plastic bags, and more specifically, to a perforation blade and method used to form an easy-open corner which resists inadvertent bursting during handling of a filled bag. Such bags are commonly used for heavy-duty applications, such as for transport, sale, and storage of materials such as chemicals, salt, fertilizer, lawn lime, potting soil, and the like. The are typically fabricated from LD, HD, or LLD polyolefin sheet or tube stock, such as polyethylene or polypropylene having a thickness in the range of 3 to 12 mils. The sheet or tube stock may be coextruded or monoextruded, and may be a single ply or multi-ply material. The multi-ply material may be multiple thicknesses of the same sheet or tube stock, or different materials to provide particular characteristics, such as strength, flexibility, UV resistance, or color. The sheet stock may also be woven or non-woven synthetic or non-synthetic material. While the invention has particular application to bags with a capacity of from 20 to 100 pounds, the present blade used to form the easy-open corner can be applied to bags of any size.
Conventional, heavy-duty bags of the prior art are typically cut along the top with a knife or other suitable tool to define a sufficiently large opening through which the contents of the bag are dispensed. In the absence of a cutting knife or tool, attempts to manually tear open the bag by hand are often futile, because of the relative thickness and durability of such bags. Once opened, the bag must generally be embraced with both arms, lifted and inverted to dispense the contents from an opening in or near the top of the bag. In many cases, this requires substantial physical effort, and sometimes results in inadvertent uncontrolled dumping or over-dumping of the contents.
In an effort to facilitate opening and control dumping, some heavy duty bags are formed with a perforated, removable corner adapted for being hand-torn to form a pourer. While such bags solve many problems of the prior art, certain disadvantages and limitations remain. Since the perforations formed at the corner of the bag typically pass entirely, or at least partially, through the end seal, the bag is prone to inadvertent rupture and spillage during transport and handling.